Portable gas lighter with magnetically operated lid

ABSTRACT

The lid of a smoker&#39;&#39;s lighter is retained normally closed by means of a magnet. The lid is spring biassed towards an open position and the magnet acts directly against the lid which is of a ferromagnetic material. A slide switch is provided to move the magnet away from the lid so as to cause the lid to open. The slide switch also makes an electrical contact which actuates an electric ignition system.

I United States Patent [1 Harris 111 3,758,262 Sept. 11, 1973 PORTABLE GAS LIGHTER WlTH MAGNETICALLY OPERATED LID [75] Inventor: Anthony Roberts Harris, Hanworth,

England [73] Assignee: Dunhill Lighters Limited, London,

England [22] Filed: July 14, 1972 21 Appl. No.: 271,671

[52] U.S. Cl 431/130, 431/132, 431/255,

317/96, 200/67 F, 292/251.5, 335/205 [51] Int. Cl. F23g 3/01 [58] Field of Search 317/81, 92, 93, 96;

[ 56] References Cited UNITED STATES PATENTS 3,442,598 5/1969 Halm 431/255 2,219,186 10/1940 l-lomfeck 292/251.5 X 2,770,697 11/1956 Kellett 335/205 2,950,139 8/1960 Carbary 292/251.5 2,983,538 5/1961 Fletcher 292/25l.5 3,025,372 3/1962 Benjetsky 200/67 F X 3,328,561 6/1967 Sakamoto et a1. 219/442 3,612,736 10/1971 Steuemagel 431/130 3,675,845 7/1972 Scheerer 292/251.5 X

Primary ExaminerVolodymyr Y Mayewsky Attorney-Joseph F. Brisebois et a1.

[5 7] ABSTRACT The lid of a smokers lighter is retained normally closed by means of a magnet. The lid is spring biassed towards an open position and the magnet acts directly against the lid which is of a ferromagnetic material. A slide switch is provided to move the magnet away from the lid so as to cause the lid to open. The slide switch also makes an electrical contact which actuates an electric ignition system.

5 Claims, 20 Drawing Figures PATENTED SE?! 1 I975 swan 3 BF 5 PORTABLE GAS LIGHTER WITH MAGNETICALLY OPERATED LID This invention relates to lighters of the type having an internal fuel reservoir and primarily intended for lighting such items as cigars, cigarettes and pipes. Such a lighter will be termed herein a smokers lighter.

It is usual to provide a'lid on a smoker's lighter to cover the burner when the lighter is not in use.

According to the prsent invention means to retain the lid of a smokers lighter normally closed comprises a magnet. Preferably, the magnet acts directly against a spring biassed lid of ferromagnetic material.

The invention can be embodied in either a pocket lighter or a table lighter.

By way of example only, a preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 shows an isometric view of a pocket smokers lighter embodying the invention,

FIG. 2 is a part sectional view illustrating the internal arrangement of parts of the lighter with certain parts omitted for clarity,

FIG. 3 shows an isometric view of potted electronic circuitry employed in the lighter and cells used for powering the lighter,

FIGS. 4a, b and show the arrangement of components in the potted electronic circuitry,

FIG. 5 is a diagrammatic isometric view of a lid catch for the lighter,

FIG. 6 is an exploded view of some of the component parts of the lid catch, I

FIG. 7 corresponds generally to FIG. 2 but shows different details of construction,

FIGS. 8 and 9 show to an enlarged scale details of construction of a base plate used in the lighter, FIG. 8 being a sectional view and FIG. 9 a plan view,

FIG. 10 illustrates the fuel tank and burner assembly of the lighter,

FIG. 1 1 shows a side elevation of the fuel tank,

FIG. 12 shows a view from beneath of the fuel tank,

FIG. 13 shows a plan view of the fuel tank,

FIG. 14 shows an exploded" isometric view of the top of the fuel tank and part of a switch mechanism,

FIG. 15 shows an exploded" isometric view of flame regulation components,

FIG. 16 shows a partly sectional view of flame regulation components,

FIG. 17 shows an insulator used in the lighter and.

FIG. 18 shows the electronic circuit of the lighter.

It should be noted that the FIGURES are not all to the same scale and that'in the interests of clarity parts may be omitted or simplified.

Referring to FIG. I, the butane gas smoker's lighter there shown comprises a hollow rectangular casing 1 having a sprung lid 2 and base plate 3, a slide switch 4, a flame adjustment wheel 5, a burner assembly 6 (only.

.a part of which can be seen in FIG. 1) and an ignition electrode 7. When the lighter is not in use the sprung lid 2 is retained closed by a magnet 8. As will be appreciated the external parts of the lighter are desirably given a high quality ornamental finish to appeal to the eye. In particular the casing 1 and base plate 3 can be made of, or plated with, a precious metal. The lid 2 is required to be in part at least of a ferromagnetic material so as. to be attracted by the magnet 8 but can of course be plated with a precious metal.

Assuming the lid 2 to be closed, the lighter is operated by depressing the slide switch 4 towards the base of the lighter whereupon the lid 2 flies open, an electrical contact is made within the lighter and a valve in the burner assembly 6 opens to allow gas to exit for ignition. The slide switch is maintained in a depressed condition and after a very short period of time (scarcely perceptible to the user) a spark is generated at the ignition electrode 7 and the gas ignites. The flow of gas is pre-set to some convenient level by means of the flow adjustment wheel 5. Pipe smokers will generally use a higher flow rate setting than cigarette smokers. After use of the lighter the sprung lid 2 is manually closed and the magnet 8 retains the lid closed until the next occasion on which the slide switch 4 is operated. Closure of the lid 2 stops the flow of gas through the burner assembly 6.

Now that a general description'of the lighter has been given its component parts will 'be described in detail. For this purpose the description can be dealt with under several separate headings, viz. general internal layout; lid catch; fuel tank; base-plate; gas control mechanism; electronic circuitry and mechanical aspects of the electronic circuitry.

GENERAL INTERNAL LAYOUT FIG. 2 show most of the major internal component parts of the lighter although certain parts are omitted for clarity of illustration. Most of the internal space is taken up by a gas tank 9 and electronic circuitry 10 potted in an epoxy resin or other suitable material. The electronic circuitry 10 is connected to a switch contact wire 11 and to a transformer 12 (T2 in the circuit diagram). The electronics circuitry 10 is potted so as to be in the shape of a rectangular box with a step therein as can be seen in FIG. 3. The step is used to accommodate two electric cells 13 which are held in a plastics material tray (not shown) including means for making connection to the cells. The cells are connected in series and the positive pole of the series connected cells is connected to the casing l.

The arrangement of parts within the potted circuitry 10 is shown in FIGS. 4a, b and c. FIG. 4a shows the component layout with a direction of view corresponding to that of FIG. 2. FIG. 4b and 4c show views at right angles to the direction of view of FIG. 4a, FIG. 4b being a side view and FIG. 40 an end view. The component reference numbers are the same as those used in the circuit diagram FIG. 18. The layout shown in FIGS. 4a, b and c is thus considered to be self-explanatory.

LID CATCH FIG. 5 shows a diagrammatic view of the lid catch. A compression spring 14 shown in broken outline is provided to urge the lid 2 open, the lid being provided with a hinge (not shown) at 15. As may best be seen in FIG. 6, the magnet 8 is generally U shaped with a north pole piece 16 and a south pole piece 17 and has a base portion 18 which is received in a rectangular yoke 19. Screws 20 and 21 are provided to bear upon and so retain the magnet 8 in the yoke 19. The slide switch 4 is attached to the yoke 19 by means of a push-fit location lug 22 received in a hole23 in the yoke 19.

FIG. 7 shows the mechanical arrangements for bias; sing the slide switch 4 in its UP position (it'should be noted that the magnet 8 is omitted from FIG. 7). A helical compression spring 24 disposd coaxially about a tube 39 forming part of the burner assembly 6 acts at its lower end against a washer 25 positioned directly beneath the yoke 19. The yoke 19 is shaped at 26 so as to conform to the shape of the tube 39 against which it lies so that the yoke can slide vertically. It will be seen that the casing 1 is recessed at 27 to provide a sliding surface for the slide switch 4. When the slide switch 4 is in its UP position and the lid 2 is closed the poles of the magnet 8 are in contact with the under surface of the lid. The lid 2 which (as previously explained) is at least in part of ferromagnetic material is retained closed against the action of the spring 14 by the force of magnetic attraction. When the slide switch 4 is depressed the poles of the magnet 3 are moved away from the lid and the force of the spring 14 becomes more powerful than the magnetic attraction and the lid springs open to assume a vertical position. The return of the lid 2 to its closed position is achieved manually.

FUEL TANK Details of the fuel tank 9 are shown in FIGS. 30 to 14. The fuel tank is moulded from a plastics material such as that known as DELRIN" (registered Trade Mark). The burner assembly 6 and filler valve 40 are moulded during manufacture of the tank into the positions shown. Burner tubes and tiller valves are components quite familiar to those skilled in the art of making smokers lighters and hence a detailed description is not necessary here. The burner assembly 6 is preferably of the type described in British Pat. No. 822,374 or No. 828,813 and the filler valve can, for example, be of the type described in British Patent Specification No. 784,357 or No. 966,967.

The fuel tank 9 includes a hole 41 for reception of switch components as will be further described later. Typically the wall thickness of the tank will be 0.04 inches.

BASE-PLATE Details of the base-plate 3 and the means by which it is retained in position are shown in FIGS. 8 and 9. Referring to FIG. 8, the lower end of the casing ii is provided with recessed portions 28 and 29. The base-plate 3 is provided with a projection 30 for entry into the recessed portion 30 and a retractible projection 31 for entry into the recessed portion 29. The base plate 3 has a groove'32 formed therein which acts as a mounting for the retractible projection 31. The retractible projection' 31 consists of a short length of springy wire of slightly smaller diameter than the width of the groove 32. The shape of the wire could generally be described as a flattened One end, 33, of the wire is secured in the groove 32 by stamping the upper wall of the groove at point to bend the upper wall towards the lower wall to trap the wire in position. A threaded screw hole 34 is provided in the base-plate 3 to receive a retaining screw 35 (shown in broken outline). When the screw 35 is removed from its hole the natural springiness of the wire causes its end 36 (shown in broken outline) to move into a position a little to the right (as shownlof the position normally occupied by the central axis of the screw 35 so that the projection 31 is retracted to allow the base-plate 3 to be removed from the casing 11 for cell replacement and refuelling. When (with the base-plate 3 in position) the screw 36 is insorted the point of the screw (which is suitably shaped) displaces the end 36 of the wire so that the projection 31 is thrust outwards into the recessed portion 29 so retaining the base-plate 3 in the casing I.

It will be understood that other types of base-plate can be used. For example, a base-plate which requires to be slid sideways against spring pressure to disengage a projection from a recess can be used. Alternatively a snap-in" type base-plate can be used. If desired a hole and dust cap, corresponding in position to the tiller valve, can be provided in the base-plate so that the lighter can be refuelled without removing the base-plate.

GAS CONTROL MECHANISM Gas control mechanisms for smokers lighters are well known to those skilled in the art and therefore a lengthy description is not necessary here. As previously stated, the burner assembly 6 is preferably of the type. described in British Patent No. 822,374 or No. 828,813. FIG. 10 shows a view of the fuel tank 9, flame adjustment wheel 5 and burner assembly 6 with other components omitted. The burner assembly 6 comprises a central spring mounted rod 42 fitted coaxially within the tube 39. The rod 42 is able to move longitudinally against the action of the spring (not shown) which urges the rod 42 upwards (as seen in the drawing). The rod 42 is connected to a valve (not shown) which allows gas from the fuel tank to exit through the tube 39 when the rod is in its UP position. The top end of the rod is arranged to act against the lid 2 ofthe lighter. When the lid 2 is closed the rod 42 is depressed against the action of the spring and the valve (not shown) is closed. When the lid is open the rod 42 moves upwards, the valve opens and gas flows out of the fuel tank 9. Closure of the lid once more depresses the rod against its spring and shuts off the gas. By this means, opening and closure of the lid 2 of the lighter is made to provide a simple but effective on/off control over the flow of gas.

The component parts of the lighter used for flame regulation are shown in FIGS. 15 and 16 (FIG. 16 being to a larger scale than FIG. 15) with other parts omitted. Flame regulation in smokers lighters is within the knowledge of those skilled in the art so that a simple description here will suffice.

The flame adjustment wheel 5 is of a resilient plastics material and has a knurled front 43 for operation by the user and a hole 44 with projections 45 arranged to push onto and mate with a splined shaft 46 on an screw member 47. Gas from the fuel tank 9 exists to the tube 39 by way of a slot 48 in a housing 49, thence through a wick 50 and a central passage 51 in a compression member 52, and thence by way of the gas on/off valve (not shown) to the tube 39. The wick 50 lies between the compression member 52 and a seating comprising a rubber pad 53 and a lower compression member 54. The screw member 47 has an external thread 55 arranged to mate with a corresponding thread in the part (not shown) in which it is fitted. Thus operation of the flame adjustment wheel 5 causes axial movement of the screw member 47 so that the wick 50 is compressed to a greater or lesser degree according to the sense of movement of the flame adjustment wheel 5. As will readily be understood, the wick 50 in a highly compressed condition will resist the passage of gas therethrough to a greater extent than when the wick is less compressed and control over the rate of flow of gas is thus achieved.

ELECTRONIC CIRCUITRY Referring to FIG. 18, a battery E is connected to supply the ignition system of the lighter which comprises an ignition switch SW1; an inverter constituted by transistors VT] and VT2, and a transformer T,; an inverter control circuit constituted by transistors VT3 and VT4; resistors R,, R R and capacitors C and C a fullwave bridge rectifier constituted by diodes D,, D D and D,; a triggering circuit constituted by triggering diode D and resistors R and R and a discharge circuit constituted by a capacitor C,, a step-up transformer T a thyristor D,,, and ignition electrodes IE. As will be explained in more detail later, operation of the switch SW1 causes the production of an electric spark at the ignition electrodes IE to ignite the fuel of the lighter. Examples of suitable types and values of components for the circuit are set out in the table below.

Component Type or Value E Two mercury cells each type MP62SH VTI, VT2, VT3 each 2N3794 R, 68k 1- 0.1W

C, 33y. F 40V electrolytic normally open single pole switch Transformer T, is preferably of the type described in British Patent Application No. 5981/72 entitled For- 4 mers for Inductive Devices and Devices and Apparatus Employing Same.

The inverter is designed to have a high efficiency so that the time taken to charge the capacitor C, can be kept low. In this respect, silicon transistors selected for low collector-emitter saturation voltage at the operating currents involved are employed in conjunction with a toroidal ferrite transformer. The bridge rectifier diodes are high frequency types also chosen to maintain high efficiency. In this respect a full-wave rectifier arrangement is preferred to a half wave arrangement.

The collectors of transistors VTl and VT2 are connected to respective ends of the primary winding P, of transformer T, and their emitters are connected in common to the negative pole of battery E. The bases of transistors VT] and VT2 are connected to respective ends of the primary winding P, of transformer T,. As will be explained in more detail later, transistors VT3 and VT-t are connected to control the base current to transistors VTl and VTZ and so control operation of the inverter. The inverter functions in a known manner as a multivibrator square-wave oscillator with transformer coupling to provide the necessary feedback.

The secondary winding of transformer T, has one end connected to the cathode of diode D, and the anode of diode D and its other end connected to the cathode of diode D, and the anode of diode D,. The anodes of diodes D, and D are connected in common to the negative pole of the battery E. The cathode of diodes D and D are connected in common to one end of trigger diode D whose other end is connected to one end of resistor R, whose other end is connected through resistor R to the negative pole of the battery E. Thyristor D, has its anode connected to the cathodes of diodes D and D and its cathode connected to the negative pole of the battery E. The trigger electrode of thyristor D, is connected to the junction of resistors R. and R,,. The full-wave rectified output of transformer T, thus appears across thyristor D Components -VT3, VT4, R,, R R,,, C, and C constitute the inverter control circuit. The emitter of transistor VT3 is connected to the centre-tap of primary-winding P of transformer l, and its collector is connected to the base of transistor VT4. The collector of transistor VT4 is connected in common to the base of transistor VT3, one end of capacitor C one end of capacitor C and one end of resistor R The emitter of transistor VT4 is connected to one end of resistor R, the other end of which is connected to the end of capacitor C remote from the base of transistor VT3. The end of resistor R remote from the base of transistor VT3 is connected to the negative pole of the battery E. Resistor R is connected from the junction of resistor R, and capacitor C to the negative pole of battery E. The common ends of resistors R, and R and capacitor C, are connected to the centre-tap of primary winding P, of transformer T, and to the pole of switch SW1 remote from the battery E. The end of capacitor C remote from transistor VT3 is connected to the positive output (cathodes D and D of the bridge circuit constituted by diodes D,, D D D.,.

The positive pole of electrolytic capacitor C, is connected to the cathodes of diodes D and D and its negative pole is connected to one end of the primary winding of transformer T The other end of the primary 0 winding is connected to the negative pole of the battery E. One end of the secondary winding of transformer T is connected to the negative pole of the battery E. The other end of the secondary winding of transformer T, is connected to the ignition electrode 7. The other ignition electrode is constituted by the rod 42 which is connected to the positive pole of the battery E. The positive pole of battery Ev is connected to the casing 1.

On closure of the switch SW1 the positive pole of the battery E is connected to the top end (as shown) of capacitor C and a positive going waveform consequently appears at the base of transistor VT3. The emitter of transistor VT3 is connected to the negative pole of the battery E by way of the centre-tap of the primary winding P, so that the said positive going waveform tends to turn transistor VT3 0N. As a result collector current for transistor VT3 isdrawn from the base of transistor VT4 which tends to turn VT4 ON. Collector current from transistor VT4 feeds the base of transistor VT3 which in turn draws more current from the base of transistor VT4. Thus, transistors VT3 and VT4 form a complementary pair switch and closure of switch SW1 results in both of transistors VT3 and VT4 turning ON. Transistor VT3 feeds base current to transistors VTl and VTZ of the inverter which oscillates and continues oscillating so long as the switch SW1 is closed to supply I When the inverter is functioning a square-wave output appears at the secondary winding S of transformer T of approximately 70V peak to peak amplitude at a frequency of approximately 40kI-iz. The output of the circuit will, of course, be somewhat less if the battery has deteriorated through age or use. The inverter and rectifier change the battery voltage from a level of a few volts to a level considerably greater.

The full-wave rectified output of the secondary winding S charged capacitor C l through the primary winding of transformer T Trigger diode D remains nonconducting until its breakdown voltage is reached and so long as the voltage across trigger diode ll) is less than the breakdown voltage the voltage drop across resistors R and R is effectively zero. A point is soon reached as capacitor C charges when the voltage across trigger diode D is equal to its breakdown voltage, whereupon the diode D conducts and a signal appears at the junction of resistors R and R which triggers the thyristor D into a state of conduction. Capacitor C now rapidly discharges through the primary winding of transformer T and thyristor D (which, of course, remains conducting until the current through it becomes equal to zero) and as a result a very high voltage (about 7kV) is induced in the secondary'winding of transformer T The high secondary voltage causes a fuel-igniting spark to occur between the ignition electrodes IE.

The energy required to ignite the butane gas of they lighter is approximately 2m] and in the present circuit at least l5mJ would be stored in capacitor C While the energy available in the spark depends upon the efficiency of the transformer T this value of stored energy in capacitor C more than compensates for expected losses in transformer T The use of trigger diode D and thyristor 1),; allows a high charging rate of capacitor C to be employed since the open circuit output voltage of the inverter and rectifier can be made significantly greater than the maximum working voltage of the capacitor C This fact is advantageous because the size of capacitors of a given value increases with their rated working voltage.

The discharge of capacitor C also results in a negative going spike being applied through capacitor C to the base of transistor VT3. This negative going spike causes both transistors VT3 and VTd of the inverter control circuit to turn OFF. As a result the flow of base current to the transistors of the inverter ceases and the inverter stops oscillating. The negative going spike will charge capacitor C, in such a manner as to maintain the transistors VT3 and VT4 OFF. This charge decays through the resistances associated with capacitor C but the transistors VT3 and VTi remain OFF until a positive going waveform is again applied at the base of transistor VT3 by a further actuation of the switch SW1.

It will be appreciated that to obtain the spark discharge the usermust continue to operate the switch SW1 for the multivibrator to function sufficiently long for the voltage on capacitor-C, to be built up. Once capacitor C has discharged it will be observed that the inverter is turned off. Thus for a single actuation of the switch the inverter runs for a sufficient time to produce the spark, after which it remains off irrespective of whether or not the user keeps the switch depressed.

The switch action does not need to be mechanically timed providing the contact is made the inverter will run only for the time necessary to charge the capacitor with sufficient energy to create one ignition spark. This means that no energy is wasted after the capacitor is fully charged (a fixed time charging system would have to allow sufficient time for a partially used battery to charge the capacitor, which would thus be more than necessary for a fresh battery). The time (normally scarcely perceptible to the user) required for the capacitor to charge and a spark to be produced will increase as the battery ages and can serve as a useful indication of the necessity to renew the battery. Nevertheless, the ignition system should continue to operate even with fairly extended charging times.

MECHANICAL ASPECTS OF THE ELECTRONIC CIRCUITRY The mechanical details of the switch SW1 are illustrated in FIG. 2 and 14. A helical compression spring (not shown) is located in the hole 41 (FIG. 14,) so as to act against the switch contact wire 11 (FIG. 2). A contact pin 56 is inserted in the end of the hole 41 remote from the contact wire 11 and is biased by the spring into contact with the internal face of the slide switch 4. The slide switch 4 is made of an insulating material with a fluted front face and an areaSfi of conducting material on its inside face. The conducting area 58 is connected to the positive pole of the battery through the casing 1 (the area 5% slides against the cats ing 1). When the slide switch 4 is in its UP position the contact pin touches thev insulated part of the slide switch 4, but when the switch 4 is depressed the pin 56 comes into contact with the area 58 and connection is made through the spring in hole 41 to contact wire 11 which in turn is connected to the electronic components.

The high voltage parts of the circuit need careful insulation to ensure that unwanted discharges do not occur. The shaping of the insulation about the ignition electrode 7 can be seen in the Figures. A shield 57 (FIGS. 1 and 17) of a ceramic or other heat resistant insulating material is placed about ignition electrode 7 to help avoid such unwanted discharges. The burner assembly 6 is connected to the positive pole of the battery E through the yoke 19 (which is of metal) and the casing 11.

It will be appreciated that the described embodiment has many advantages over prior art lighters. The provision of the inverter and rectifier to change the level of voltage supplied by the battery to a higher level enables a smaller capacitor to be employed for the storage of a given amount of energy than if the capacitor has been charged by the battery alone. This provides an advantageous economy in the space requiredwithin the lighter; for the electrical components (the height of the lighter shown in FIG. 1 can be as little as 7 cms). Further, low voltage cells are employed which are relatively cheap and easily obtainable. The use of the inverter also provides a rapid means for charging the capacitor which is desirable in respect of repeated operation of the lighter and further no load is imposed on the cells during a pe riod of non-use. The use of the trigger diode is particularly advantageous in respect of the speed of charging the capacitor and the use of the thyristor ensures a rapid discharge of the capacitor without any problems of the "contact bouncef'type (a thyristor, once triggered, remains conducting until the voltage across it drops to zero). I

Other forms and modifications are possible within the scope of the invention. For example, the invention can be embodied in a table lighter. in a table lighter a more squat arrangement of components would generally be desirable. The thyristor can if desired be replaced by a mechanical switch contact and the trigger diode can be omitted, but the use of the components shown to provide automatic ignition is preferred. Transistors of the opposite conductivity types to those shown can be employed and other inverter arrangements are possible. For example, an oscillator employing a single transistor could be used. The inverter could employ a piezo-electric solid-state transformer. It is also contemplated that a voltage multiplier of the diode voltage-doubler type could be used. At least some of the electrical components of the lighter could be made in integrated circuit fonn. One or more rechargeable cells could be used to power the lighter. it is not essential for the electronic components to be potted as described.

I claim:

I. A smokers lighter comprising:

an outer casing of such small dimensions that the lighter can be used as a pocket lighter,

a lid having at least a part of ferromagnetic material, said lid forming an openable part of said casing and being connected thereto by hinge means,

spring means arranged to urge said lid to an open position,

a fuel tank mounted in the casing,

a gas control valve connected to said fuel tank to control the flow of gas therefrom and arranged to open when the lighter is operated,

a burner assembly mounted in the casing so as to be covered by said lid in its closed position and connected to receive gas from the gas control valve,

a magnet assembly movably mounted in the casing and arranged to act directly on said lid in its closed position to retain said lid closed against the force exerted by the spring means,

cell holder means mounted in the casing and adapted to receive at least one electric cell,

a spark ignition circuit electrically connected to said cell holder means,

switch means connected in said spark ignition circuit to control the operation thereof,

spark ignition electrode means connected to the output of said spark ignition circuit and mounted in the casing so as to co-operate with the burner assembly to ignite gas issuing therefrom, and

actuating means having an exterior part adapted for manual operation, said actuating means being coupled to said magnet assembly and said switch means, and being operative upon manual operation of said exterior part to move said magnet assembly away from said lid so as to decrease the force of magnetic attraction thereon to allow the lid to open under the force exerted by said spring means, and to actuate said switch means.

2. A lighter as claimed in claim 1, wherein the casing is generally rectangular, the lid forms a part of the top face of the casing, and said exterior part of said actuating means is located in a side face of said casing.

3. A lighter as claimed in claim 1, wherein said burner assembly includes an elongate burner tube, said magnet assembly includes a generally U-shaped magnet having a pole-piece on each side of said burner tube, and said magnet assembly is mounted on resilient mounting means biassing said magnet assembly towards said lid in its closed position.

4. A smokers lighter comprising:

an outer casing provided with an openable lid, the lid having at least a part of ferromagnetic material,

spring means arranged to urge said lid to an open position,

a fuel tank mounted in the casing,

a burner ssembly including a gas control valve, said assembly being mounted in the casing so as to be covered by said lid in its closed position and being connected to the fuel tank,

a sensor rod forming part of the burner assembly, said rod being biassed against the lid in its closed position and adapted to open said gas control valve when said lid is opened and to close said valve when said lid is closed,

a magnet assembly movably mounted in said casing, arranged to retain said lid closed by the force of magnetic attraction,

cell holder means mounted in the casing and adapted to receive and make electrical connection to at least one electric cell,

a circuit for generating a high voltage electric spark connected to said cell holder means,

mechanically operable contact means connected in said circuit to actuate said circuit on closure of the contact means,

spark electrode menns connected to the output of said circuit and mounted in the casing so as to cooperate with said burner assembly to ignite gas issuing therefrom, and

actuating means having a part on the outside of said casing adapted for manual operation, said actuating means being coupled to said magnet assembly and said switch means, and being effective when said manual operation is performed to move said magnet assembly to decrease the magnetic attraction on the lid to allow said lid to open under the influence of said spring means, and to close said contact means, thereby effecting automatic opening and lighting of the lighter.

5. A lighter as claimed in claim 4, wherein said burner assembly includes flame adjustment means comprising: I

wick means located in the path of gas through the burner assembly,

a compression member arranged to compress said wick means to increase its resistance to gas flow, and

a manually operable flame control coupled to said compression member to adjust the degree of compression of said wick means.

t 0 fi 

1. A smoker''s lighter comprising: an outer casing of such small dimensions that the lighter can be used as a pocket lighter, a lid having at least a part of ferromagnetic material, said lid forming an openable part of said casing and being connected thereto by hinge means, spring means arranged to urge said lid to an open position, a fuel tank mounted in the casing, a gas control valve connected to said fuel tank to control the flow of gas therefrom and arranged to open when the lighter is operated, a burner assembly mounted in the casing so as to be covered by said lid in its closed position and connected to receive gas from the gas control valve, a magnet assembly movably mounted in the casing and arranged to act directly on said lid in its closed position to retain said lid closed against the force exerted by the spring means, cell holder means mounted in the casing and adapted to receive at least one electric cell, a spark ignition circuit electrically connected to said cell holder means, switch means connected in said spark ignition circuit to control the operation thereof, spark ignition electrode means connected to the output of said spark ignition circuit and mounted in the casing so as to cooperate with the burner assembly to ignite gas issuing therefrom, and actuating means having an exterior part adapted for manual operation, said actuating means being coupled to said magnet assembly and said switch means, and being operative upon manual operation of said exterior part to move said magnet assembly away from said lid so as to decrease the force of magnetic attraction thereon to allow the lid to open under the force exerted by said spring means, and to actuate said switch means.
 2. A lighter as claimed in claim 1, wherein the casing is generally rectangular, the lid forms a part of the top face of the casing, and said exterior part of said actuating means is located in a side face of said casing.
 3. A lighter as claimed in claim 1, wherein said burner assembly includes an elongate burner tube, said magnet assembly includes a generally ''''U''''-shaped magnet having a pole-piece on each side of said burner tube, and said magnet assembly is mounted on resilient mounting means biassing said magnet assembly towards said lid in its closed position.
 4. A smoker''s lighter comprising: an outer casing provided with an openable lid, the lid having at least a part of ferromagnetic material, spring means arranged to urge said lid to an open position, a fuel tank mounted in the casing, a burner ssembly including a gas control valve, said assembly being mounted in the casing so as to be covered by said lid in its closed position and being connected to the fuel tank, a sensor rod forming part of the burner assembly, said rod being biassed against the lid in its closed position and adapted to open said gas control valve when said lid is opened and to close said valve when said lid is closed, a magnet assembly movably mounted in said casing, arranged to retain said lid closed by the force of magnetic attraction, cell holder means mounted in the casing and adapted to receive and make electrical connection to at least one electric cell, a circuit for generating a high voltage electric spark connected to said cell holder means, mechanically operable contact means connected in said circuit to actuate said circuit on closure of the contact means, spark electrode menns connected to the output of said circuit and mounted in the casing so as to co-operate with said burner assembly to ignite gas issuing therefrom, and actuating means having a part on the outside of said casing adapted for manual operation, said actuating means being coupled to said magnet assembly and said switch means, and being effective when said manual operation is performed to move said magnet assembly to decrease the magnetic attraction on the lid to allow said lid to open under the influence of said spring means, and to close said contact means, thereby effecting automatic opening and lighting of the lighter.
 5. A lighter as claimed in claim 4, wherein said burner assembly includes flame adjustment means comprising: wick means located in the path of gas through the burner assembly, a compression member arranged to compress said wick means to increase its resistance to gas flow, and a manually operable flame control coupled to said compression member to adjust the degree of compression of said wick means. 